Comparing ‘AI’ For Basic Plant Care With Human Brown Thumbs

April 29, 2025 by Maya Posch 18 Comments

The future of healthy indoor plants, courtesy of AI. (Credit: [Liam])

Like so many of us, [Liam] has a big problem. Whether it’s the curse of Brown Thumbs or something else, those darn houseplants just keep dying despite guides always telling you how incredibly easy it is to keep them from wilting with a modicum of care each day, even without opting for succulents or cactuses. In a fit of despair [Liam] decided to pin his hopes on what we have come to accept as the Savior of Humankind, namely ‘AI’, which can stand for a lot of things, but it’s definitely really smart and can even generate pretty pictures, which is something that the average human can not. Hence it’s time to let an LLM do all the smart plant caring stuff with ‘PlantMom’.

Since LLMs so far don’t come with physical appendages by default, some hardware had to be plugged together to measure parameters like light, temperature and soil moisture. Add to this a grow light and a water pump and all that remained was to tell the LMM using an extensive prompt, containing Python code, what it should do (keep the the plant alive), and what Python methods are available. All that was left now was to let the Google’s Gemma 3 handle it.

To say that this resulted in a dramatic failure along with what reads like an emotional breakdown on the part of the LLM would be an understatement. The LLM insisted on turning the grow light on when it should be off and had the most erratic watering responses imaginable based on absolutely incorrect interpretations of the ADC data, flipping dry and wet. After this episode the poor chili plant’s soil was absolutely saturated and is still trying to dry out, while the ongoing LLM experiment, with an empty water tank, has the grow light blasting more often than a weed farm.

So far it seems like that the humble state machine’s job is still safe from being taken over by ‘AI’, and not even brown thumb folk can kill plants this efficiently.

The measurement results of: (a) RSSI in dBm collected from gateway 2 and (b) soil moisture during the winter period. (Credit: Maja Škiljo et al., 2022)

Using LoRa Nodes As Soil Moisture Sensing Antennas

October 2, 2023 by Maya Posch 9 Comments

Implementation of LoRaWAN-based soil moisture sensing device. (Credit: Maja Škiljo et al., 2022)

Although we generally think of Internet of Things (IoT) and similar devices as things that are scattered around above ground, there are plenty of reasons to also have such devices underground. These so-called IoUT devices are extremely useful when it comes to monitoring underground structures, but communication via radiowaves is obviously impacted when soil is in the way. Although there are ways to get around this, a 2022 paper by Maja Škiljo and colleagues in Sensors covers an interesting way to make use of this signal attenuation property of changing moisture levels in soil.

By quantifying the exact attenuation of the signal received at the gateways, they were able to determine the soil moisture levels around the LoRa node which had been buried at a depth of approximately 14 centimeters. This LoRa node used off-the-shelf components consisting of an ATmega328P-based Arduino Pro Mini and SX1276-based RFM95W LoRa module with a spring antenna.

During experimentation in- and outdoors it was determined that a narrowband, printed (PCB) antenna was optimal for soil moisture sensing purposes. Other than the interesting question of how to keep soil moisture sensing nodes like this powered up over long periods of time (perhaps periodic retrieval to replenish the battery), this would seem to be a very interesting way to monitor the soil moisture levels in something like a field, where each node can provide its own ID and the received signal providing the relevant data in the form of the SNR and other parameters recorded by the gateway.

(Heading image: The measurement results of: (a) RSSI in dBm collected from gateway 2 and (b) soil moisture during the winter period. (Credit: Maja Škiljo et al., 2022) )

Comparing Cheap Capacitative Soil Moisture Sensors With Commercial Sensors

February 1, 2023 by Maya Posch 41 Comments

When your residence has soil moisture sensors embedded that were dictated by your friendly neighborhood HoA, you may start asking questions about the system used. That’s what [Modest Maker] did and the resulting findings along with an attempt to beat the commercial system with some cheap capacitive sensors, are covered in a recent video that’s also embedded below. Part of the motivation here was that the commercial system in the community was not clearly installed properly.

To make a long story short, the commercial system by Hunter (Soil-Clik) appears to be a tensiometer-based system that uses the pressure produced by moisture intrusion into the measurement column. This translates to how easy it is for plant roots to extract water, depending on the soil type. [Modest Maker] had to first dodge the broken-by-design capacitive sensors that are available everywhere, but after that was able to cobble together a measurement system that he hopes will allow him to validate the commercial system’s installation.

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Fytó Is Fido For Phytophiles

August 15, 2022 by Kristina Panos 5 Comments

On the surface, most plants really aren’t all that exciting, save for maybe the Venus flytrap. Sure, you can watch them grow in the long run, but for the most part, they’re just kind of there, quietly bringing peace and cleaner air. Day by day, they hardly move at all, although if you’re one of those people who likes to get the Sim into the pool and take the ladder away, you could always play the drought game just to watch it droop and come back to life a half hour later.

Fytó the smart planter is a much more cool and far less cruel way of spicing up your plant life. The idea is to turn a plant into a pet by giving it an expressive face. Sure, plants have needs, but they communicate them more subtly than the average Earthing. By assigning animated emoji to various conditions, the plant becomes more familiar and in turn, feels more like a pet. Plus, the whole thing is just so darn cute.

Fytó runs on a Raspberry Pi 2W and has six emotions that are based on a capacitive soil moisture sensor, an LM35 temperature sensor, and an LDR module to detect light levels. If everything is copacetic, Fytó puts on a happy face, and will lick its lips after getting a drink of water. If the light is insufficient, Fytó looks sleepy; if the plant needs water, Fytó appears sweaty, red-faced, and parched. Don’t conflate this with the temperature-taking emoji, which indicates that Fytó is too hot. Finally, if the spot is too drafty and cold, Fytó looks like it’s nearly frozen. Be sure to check out the video after the break and watch Fytó work through their range of emotions.

Would you rather hear your plant complain in English? There’s a build for that.

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A soil moisture sensor with silkscreen chipped and copper corroded

Soil Moisture Sensor Coating Lessons Learned The Hard Way

March 2, 2022 by Arya Voronova 35 Comments

Ever wanted to measure soil moisture? Common “soil moisture meter module arduino raspberry compatible free shipping” PCBs might deceive you with their ascetic looks. Today, [Raphael (@rbaron_)] is here to teach us (Twitter, unrolled) what it takes to build a soil-embedded sensor that can actually survive contact with a plant.

As the picture might hint, waterproofing is of paramount importance, and soldermask doesn’t quite cut it. Raphael describes his journey of figuring out approaches and coatings that would last, starting from simply using nail polish, and ending with the current option – a rotisserie-like device that rotates sensors as the coating applied to them dries, mitigating a certain kind of structural failure observed long-term. With plenty of illustrative pictures and even a video of the rotisserie device in action, you’ll quickly learn things that took time and effort for Raphael to figure out.

This isn’t the first time Raphael shares some design battlefield stories and lessons with us – he has taught us about overall capacitive moisture sensor principles, too! If that interests you, we’ve covered quite a few moisture sensor designs, from cheap but hardy two-nails designs to flip-dot-equipped ones, and some of us take the commercial designs and upgrade them!

We thank [Chaos] for sharing this with us!

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Photo of an automated plant watering system attached to four potted plants.

Automation Allows You To Leaf Your Plants Alone

November 5, 2021 by Stephen Ogier 11 Comments

The greatest threat to a potted plant stems from its owner’s forgetfulness, but [Sasa Karanovic] has created an automation system that will keep his plants from getting too thirsty. Over the past year [Sasa] has been documenting an elegant system for monitoring and watering plants which has now blossomed into a fully automated solution.

If you haven’t seen the earlier stages of the project, they’re definitely worth checking out. The short version is that [Sasa] has developed a watering system that uses I²C to communicate with soil moisture, temperature, and light sensors as well as to control solenoids that allow for individual plants to be watered as needed. An ESP32 serves as a bridge, allowing for the sensors to be read and the water to be dispensed via an HTTP interface.

In this final part, [Sasa] integrates his watering system into a home automation system. He uses a MySQL database to store logs of sensor data and watering activity, and n8n to automate measurement and watering. If something isn’t quite right, the system will even send him a Telegram notification that something is amiss.

If you think automation might be the best way to save your plants from a slow death, [Sasa] has kindly shared his excellent work on GitHub. Even if you don’t have a green thumb, this is still a great example of how to develop a home automation solution from scratch. If you’re more interested in television than gardening, check out [Sasa]’s approach to replacing a remote control with a web interface!

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Check Soil Moisture At A Glance With This Useful Display

June 18, 2021 by Lewin Day 6 Comments

Keeping soil moist is key to keeping most plants happy. It can be a pain having to dip one’s fingers into dirty soil on the regular, so it’s desirable to have a tool to do the job instead. [Andrew Lamchenko] built a capable soil moisture monitor, and equipped it with an E-ink display for easy readings at a glance.

The device is built around the NRF52810 or other related NRF52 microcontrollers, which run the show. Rather than using an off-the-shelf sensor to determine soil conditions, an LMC555CMX timer chip is used, a variant of the classic 555 timer designed for low power consumption. Combined with the right PCB design, this can act as a moisture sensor by detecting capacitance changes in the soil. The sensor is also able to send data using the MySensor protocol, allowing it to be used as a part of a home automation system.

The soil is tested periodically with the moisture sensor, and displayed on the attached e-ink screen. Since the e-ink display requires no electricity except when rewriting the display, this allows the sensor to operate for long periods without using a lot of battery power. The soil can be checked, the display updated, and then the entire system can be put to sleep, using tiny amounts of power until it’s time to test the soil again.

It’s a great example of design for low power applications, where component selection really is everything. We’ve featured [Andrew]’s projects before; he’s long been a fan of using e-ink displays to create long-lasting, low power budget sensor platforms. Video after the break.

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